Governing mechanism for mixed-pressure turbines.



0. JUNGGREN & A. T. GRAY. GOVBRNING MBGHANISM FOR MIXED PRESSURE'F.UBBINES. APPLICATION FILED JULY 29, 1911.

1,017,555, Patented Feb. 13, 1912.

ollexavwclercrag, bs M NITED STATES PATEN OFFICE;

OSCAR JUNGGREN AND ALEXANDER T. GRAY, OF SCHENECTADY, NEW YORK, ASSIGN-ORS TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

GOVERNING MECHANISM FOR MIXED-PRESSURE TURBINES.

To all whom it may concern:

Be it known that we, OSCAR JUNGGREN, a citizen of the United States, andALEXANDER T. GRAY, a subject of the King of Great Britain, residing atSchenectady, county of Schenectady, State of New York, have inventedcertain new and useful Improvements in Governing l/Iechanism for Mixed-Pressure Turbines, of which the following is a specification.

This invention relates to what are known as mixed pressure turbines, orin other words, elastic fluid turbine engines driven normally by steamor other elastic fluid at a low pressure, but provided with means foradmitting steam or other elastic Huid at high pressure whenever it isnecessary to supplement the supply of low pressure fluid, in order tocarry an increased load or compensate for a falling off in the supply ofsaid low pressure fluid. In such a machine, it is of course necessarythat the low pressure valve or valves shall be opened to their fullextent, or nearly so, before the high pressure valve or valves begin toopen, and on the other hand that the high pressure valve or valves shallbe nearly or entirely closed, before the low pressure valve or valvesbegin to close.

The present invention consists in improved mechanism for accomplishingthese objects, as hereinafter set forth and particularly pointed out inthe claims.

In the accompanying drawings, Figure 1 is an end elevation of ahorizontal turbine equipped with our improved valve gear, butdiagrammatically rendered to illustrate the relations of the parts moreclearly when all the valves are open; Fig. 2 is a side elevation, partlyin section, of the high pressure valve-operating devices; and Fig. 3 isa sectional elevation of the pilot valve and adjacent parts.

The turbine shown is of the horizontal type, having a casing 1 supportedon a base 2. Certain sets of nozzles are supplied with low pressuresteam through a large conduit 3, while another nozzle or set of nozzlesreceives steam of high pressure through a pipe 4 entering a steam chest5. The low pres sure conduit is controlled by a valve 6, preferably ofthe butterfly type, which is actuated in its opening and closingmovements by a crank arm 7 connected by a rod 8 to a Specification ofLetters Patent.

Application filed July 29,

Patented Feb. 13, 1912.-

1911. Serial No. 641,264.

lever 9 which is arranged to be actuated by the movements of a motorcontrolled by the speed governor 10. This same motor also actuates thevalve or valves controlling the admission of high pressure steam, butits actuation of the low pressure and high pressure valves is no-tsimultaneous but successive, opening the former before the latter, andclosing the latter before the former.

The lever 9 is fulcrumed in a bracket 11 forming part of the frame ofthe motor and carrying antifriction rollers 12 between which is guided aslide 13, adapted to move vertically and containing a cam slot 14engaging with a roller on a pin v15 projecting from one side of theupper end of the lever 9. The lower portion of the slot 14 is oblique tothe line of movement of the slide, so that it will cause the lever torock on its fulcrum as the slide is forced down. The upper portion ofsaid slot is longitudinal, so as to produce no movement of the leverduring the latter part of the downward movement of said slide. Theextent and arrangement of the oblique or active portion of the slot aresuch as to turn the butterfly valve from its closed position to one inwhich it is wide open, during the time that the lever 9 is beingactuated by said slot. The motor is connected both to the slide and tothe high pressure valves so that they will be opened in succession assaid slide passes downward after having opened the butterfly valve.

The motor is preferably a cylinder 16 containing a piston 17 secured toa rod 18 attached at its upper end to a head 19 to which is also securedthe rod 2O whose lower end is connected with the slide. This connectionis preferably yielding, as by means of the spring 21, so that the dangerof breakage in case the butterfly valve should seat before end of strokeis reached, will be minimized. On one side of the head 19 is a rack 22which meshes with a pinion 23 mounted on the cam shaft 24 of the valvegear for the high pressure valves. There are several of these valves,four cams being shown` in the drawing, but any desired number beingwithin the scope of our invention. The valves are of a well knownconstruction, being puppet valves 25 each controlling the opening 26from the steam chest 5 to an additional nozzle or nozzles. Each x@valveis operated by a lever 27, one end of which rests upon a cam on the camshaft 211. These cams are so disposed that they operate their valves insuccession, and this does not happen until after the slide 13 has movedso far down that the vertical or idle portion of its cam slot hasengaged the wrist pin 15 on the lever 9, and looked the butterfly valvein its wide open position.

The piston 17 is actuated by hydraulic pressure admitted to the cylinder16 through a chest 9.8 in which is a pilot valve 29 controlling theports which connect said chest with said cylinder. The hydraulicpressure enters through the pipe 3() and exhausts through the pipe 31.lhen the pilot valve is moved downward, it admits pressure under thepiston 17 to cause it to rise and shut 0H the steam more or less.Conversely7 the upward movement of the pilot valve produces acorresponding downward movement of the piston 17 and a greater admissionof steam to the turbine. These movements of the pilot valve are effectedby the speed governor 10, whose weights 32 are arranged to actuate alever 33 connected by a rod 34k with a floating lever 35 pivoted nearits middle to the stem 36 of the pilot valve and at its farther end to alink 37 connected to a lever 38, fulcrumed at one end on the frame ofthe turbine and connected at its other end by link 39 to the head 19 ofthe motor. l/Vhenever,

`by reason of a change in the load on the turbine or otherwise, theweights of the speed governor alter their position, they move the systemof levers set forth, and produce a longitudinal movement of the stem ofthe pilot valve, causing it to open a port to admit pressure above orbelow the piston 17 as the case may be. As soon as the motor has movedfar enough to change the admission of steam to correspond with thealtered load, the pilot valve will have been broughtl back to itsmid-position by reason of the floating lever and its connection with thehead 19. In its mid-position said pilot valve cuts o the pressure fromboth ends of the motor, whose piston then remains stationary holding thesteam valves in their new positions.

It will 'be seen that as the load falls off, the speed of the turbinetends to increase, so that the motor gradually lifts the slide 13 untilfinally when all t-he high pressure valves have been closed, the'oblique active portion of the slot 14 begins to operate on the lever 9to close the butteriy valve. If the reduction of load continues, thebutterfly valve will be turned farther and farther toward its closedposition, to shut off the low pressure steam until the supply is justsufficient to carry the load. l/Vhen the load begins to increase, theopposite effect occurs.

Upon reference to Fig. 1 it will be observed that the slide 13 and itsactuating` mechanism are arranged at one end of the turbine andapproximately in the upright axial plane thereof. This makes a compactarrangement and yet gives easy access to the parts. Moreover, the rod Sis short, and can be led off to either side of the machine toaccommodate itself to the location of the low pressure conduit. The rack22 which operates the cam shaft 24k engages the pinion 23 at a pointmidway of said shaft instead of out at one end as heretofore. Thisparticular location of the slide and motor therefore possesses greatpractical advantages, and has been adopted in a number of installations.

In accordance with the provisions of the patent statutes, we havedescribed the prinn ciple of our invention, together with the apparatuswhich we now consider to represent the best embodiment thereof; but wedesire to have it understood that the apparatus shown is onlyillustrative and that the invention can be carried out by other means.

What we claim as new and desire to secure by Letters Patent of theUnited States, is

1. In a mixed pressure turbine, the combination with a low pressurevalve and high pressure valves, of a motor adapted to operate saidvalves, and a slide connected to said motor and having a cam grooveadapted to actuate the low pressure valve during a part of its movementonly.

2. In a mixed pressure turbine, the combination with a low pressurevalve and high pressure valves, of a motor, a slide actuated thereby andhaving a slot containing an oblique portion and a longitudinal portion,and a lever connected to the low pressure valve and engaging with saidslot.

3. In a mixed pressure turbine, the combination with a low pressurevalve and high pressure valves, of a motor, a slide actuated thereby andhaving a slot containing an oblique portion and a longitudinal portion,a lever connected to the low pressure valve and engaging with said slot,and a cam shaft geared to said motor and arranged to actuate said highpressure valves during the time that the lever is engaged with thelongitudinal portion of said slot.

4. In a mixed pressure turbine, the combination with the low pressureconduit, of a butterfly valve therein, a lever for turning said valve, aslide having a cam slot therein provided with an active portion foractuating said lever and an idle portion for holding said lever lockedduring the further movement of said slide.

5. In a mixed pressure turbine, the combination with the low pressureconduit, of a butterfly valve therein, a lever for turning vsaid valve,a slide having a cam slot therein provided with an active portion foractu ating said lever and an idle portion for holding said lever lockedduring the further movement of said slide, and high pressure proximatelyin the upright axial plane of 10 valve gear operative only during thetime said turbine. that said lever engages said idle portion of InWitness whereof, We have hereunto set said slot. our hands, this 27thday of July, 1911. 6. The combination With a turbine prO- @SCAR JUNGGRE.vided with high pressure valves and a 10W ALEXANDER T. GRAY.

pressure valve, of a motor for actuating Witnesses: said valves insuccession, said motor being BENJAMIN B. HULL, located at one end ofsaid turbine and ap- HELEN ORroRD.

Copies of this patent may be obtained for ve cents each, by addressingthe Commissioner of Patents, Washington, D. C.

